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Biomedical subjects

S Smirne

Publications and source records attributed to S Smirne.

At least 91 records · Page 5Linked to original sources
PubMed1988

Effect of after-dinner administration on the pharmacokinetics of oral flunitrazepam and loprazolam.

The pharmacokinetics of two benzodiazepine hypnotics, flunitrazepam and loprazolam, was determined on two occasions in two groups of eight healthy volunteers. Single 2-mg oral doses of either drug were given in the fasting state at morning on one occasion and after a standard dinner at night on another. Compared with administration of drugs in the fasting state, administration of the drugs after dinner decreased peak plasma concentrations, delayed the time to reach maximum concentration, and prolonged the absorption half-life. The extent of absorption was reduced for flunitrazepam but not for loprazolam. The elimination half-life of both flunitrazepam and loprazolam was not changed in the two conditions. These changes may be of clinical significance because they can delay and reduce the effects of the drugs.

Administration, Oral↗
PubMed1988

Pharmacokinetics and bioavailability of intravenous and oral chlordesmethyldiazepam in humans.

Six healthy, fasting volunteers were given single doses of chlordesmethyldiazepam by 1 mg i.v., or as drops or tablets. Chlordesmethyldiazepam and its metabolite, lorazepam, in multiple plasma samples and in urine collected for 120 h after each dose were determined by electron-capture GLC. Mean kinetic variables for intravenous chlordesmethyldiazepam were: volume of distribution, 1.71 l.kg-1; elimination half-life, 113 h; total clearance, 0.21 ml.min-1.kg-1; cumulative excretion of lorazepam glucuronide 24.2% of the dose. Following a lag time of 15.5 min (tablets) and 4.2 min (drops), which were significantly different, the absorption of oral chlordesmethyldiazepam was a first order process, with apparent absorption half-life values averaging 1.5 h (tablets) and 1.1 h (drops). Bioavailability was 77% for tablets and 79% for drops.

Absorption↗
PubMed1988

Effects of long-lasting antiepileptic therapy on brainstem auditory evoked potentials.

The brainstem auditory evoked potentials of 84 epileptic patients in chronic monotherapy with carbamazepine (n = 36), phenobarbital (n = 19), Na-valproate (n = 20) or progabide (n = 9) were studied. The mean values of I-III and I-V interpeak latencies (IPLs) were respectively 2.16 +/- 0.11 and 4.03 +/- 0.17 in the control group, 2.31 +/- 0.09 and 4.17 +/- 0.16 in the valproic group, 2.30 +/- 0.17 and 4.19 +/- 0.20 in the carbamazepine group, 2.17 +/- 0.16 and 4.10 +/- 0.18 in the phenobarbital group and 2.16 +/- 0.11 and 4.12 +/- 0.17 in the progabide group. The prolongation of I-III and I-V IPLs was statistically significant only for the valproic acid and carbamazepine groups. Neither duration of the epilepsy and treatment and frequency of seizures nor the serum drug levels were correlated with I-V IPL values.

Adolescent↗
PubMed1988

Neuroendocrinological function in Alzheimer's disease.

The neuroendocrine function is regulated by several neurotransmitters (acetylcholine, dopamine, somatostatin and noradrenaline) known to be reduced in brains of patients with Alzheimer's disease (AD). Moreover, the hypothalamus also has pathological changes. In spite of these findings suggesting neuroendocrine dysfunctions, this function has seldom been investigated in AD patients so far. We have compared patients with clinically 'probable' AD of mild-to-moderate severity with nondemented age- and sex-matched controls. Plasma levels of prolactin (PRL), growth hormone (GH) and thyroid-stimulating hormone (TSH) were measured by commercially available radioimmunoassays (RIA) before and after stimulation with metoclopramide, l-dopa or thyrotropin-releasing hormone. Basal plasma levels of beta-endorphin and beta-lipotropin were measured by RIA after high-performances liquid chromatography. Basal and stimulated plasma levels of PRL, GH, TSH and beta-lipotropin were similar in the two groups. Basal lamina levels of beta-endorphin were significantly higher in the patient group. Of doubtful clinical importance, this might be attributed to decreased tuberoinfundibular dopaminergic activity and has also been seen in patients with Parkinson's disease.

Aged↗
PubMed1988

Effect of food on absorption of chlordemethyldiazepam.

The kinetics of a single 1-mg oral dose of chlordemethyldiazepam (CDDZ, En) was determined on two occasions in 8 healthy volunteers. CDDZ was given in the fasting state on one occasion and following a standard meal on another. Compared with the fasting state, administration of CDDZ with food prolonged the time to reach peak concentration (1.5 vs. 6.8 h after dosage, p less than 0.01) and the absorption half-life (28 vs. 231 min, p less than 0.01). Total area under the curve was not influenced, nor was CDDZ elimination half-life (84.2 vs. 88.7 h). Thus administration of CDDZ with food slows the rate of its absorption but does not alter the completeness of absorption.

Adult↗
PubMed1987

Peripheral neuropathy associated with experimental plasma cell neoplasm in the mouse.

In order to investigate the role of paraproteins in the production of neuropathy we experimentally induced monoclonal immunoglobulin-producing tumours into 32 BALB/c mice by injecting mineral oil or pristane intraperitoneally. In 11 mice morphologic and histometric studies of the sciatic nerve revealed the presence of neuropathy. Immunohistochemical studies did not demonstrate a significant amount of immunoglobulins and light chains in the endoneurium. The advantages and limits of this experimental model are discussed.

Animals↗
PubMed1986

Plasma beta-endorphin and beta-lipotropin in patients with Parkinson's disease.

Experimental and human data in young volunteers suggest that tuberoinfundibular dopaminergic systems physiologically inhibit pituitary secretion of beta-endorphin. This hypothesis was verified in patients with Parkinson's disease, a human model of a selective deficit of dopamine. Both previously untreated patients and patients who had been without chronic treatment for 1 week showed plasma beta-endorphin levels significantly higher than those of healthy age-matched controls. Plasma beta-lipotropin levels of patients and of controls were similar. There was no correlation between plasma opioid levels and age, severity, or duration of the disease. In five patients retested during chronic treatment, plasma levels both of beta-endorphin and of beta-lipotropin significantly decreased. This decrease approximately paralleled clinical improvement. The finding that in Parkinson's disease there is a reversible disinhibition of pituitary secretion of beta-endorphin confirms that this secretion is physiologically inhibited by tuberoinfundibular dopaminergic systems.

Aged↗
PubMed1986

Signs of cardiac autonomic dysfunction during sleep in patients with Alzheimer's disease.

Autonomic nervous system (ANS) failure may be an important complication in some neurological diseases. Conventional tests for the assessment of ANS functions during wakefulness cannot be used for many patients with dementia of the Alzheimer's type (DA) because of their poor cooperation. In 6 of 16 patients with presenile DAT we found signs of sympathetic cardiac dysfunction during sleep, measured as the decrease in body movement-related heart rate variation (Rbm). The study of Rbm during sleep seems to be a useful tool for ascertaining ANS function in DAT. The presence or absence of ANS dysfunction could be a more reliable criterion than age of onset for identifying subgroups of this disease.

Aged↗
PubMed1984

Effects of long-term antiepileptic therapy on the hypothalamic-pituitary axis in man.

Effects of long-term antiepileptic therapy on the hypothalamic-pituitary axis were evaluated from the basal and stimulated plasma levels of growth hormone (GH) and prolactin (PRL) and from circadian adrenocorticotropic hormone (ACTH)/cortisol rhythms. Data for patients with well-controlled epilepsy of mild-to-moderate severity were compared with those for normal healthy volunteers. Analysis of the effects of each antiepileptic drug (AED) and of combined AEDs revealed minor abnormalities of stimulated GH secretion in all treated patients. In epileptic men, all individual AEDs (except valproate) and AED polytherapy increased both basal and stimulated plasma levels of PRL. In epileptic women, this effect was more variable and less marked, probably because of early depletion of PRL reserves. Each AED and combined AEDs did not significantly change circadian ACTH/cortisol rhythms in epileptic patients. The effects observed seem not to be related to epilepsy per se. Clinical implications, pathways, and neurotransmitters involved and possible mechanisms of the neuroendocrine effects of long-term AED therapy are discussed.

Adrenocorticotropic Hormone↗
PubMed1984

Cognitive deficits and their relationship to other neurological complications in chronic alcoholic patients.

In randomly selected chronic alcoholics hospitalised for the first time for detoxification a high prevalence (68%) of cognitive deficits was found. Peripheral neuronal damage was seen in 74%, autonomic neuronal damage in 24%. Cognitive deficits were not correlated with age, daily ethanol intake, duration of alcohol abuse or severity of liver damage. There was no correlation of peripheral, autonomic and central nervous system damage. Alcohol-induced damage of the nervous system is a common complication of chronic alcoholism, whose clinical importance often obscures possible concomitant liver damage.

Adult↗
PubMed1982

Decreased CSF concentrations of homovanillic acid and gamma-aminobutyric acid in Alzheimer's disease. Age- or disease-related modifications?

Fifteen patients, 48 to 72 years old, with Alzheimer's disease were studied. Clinical status was assessed by neurologic and neuropsychologic examinations and psychometric testing. Patients were divided into two groups on the basis of clinical assessment: group 1, little mental deterioration, and group 2, serious mental deterioration. Nineteen subjects, 27 to 72 years old, without neurologic disease served as controls. Levels of homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA), and gamma-aminobutyric acid (GABA) were determined in lumbar CSF by fluorimetric or radioreceptor binding (GABA) methods. The HVA concentrations increased with age in the controls, whereas the GABA levels decreased with age and 5-HIAA levels were not modified. When compared with the age-matched controls, the patients with Alzheimer's disease showed low concentrations of HVA but not of 5-HIAA or GABA. The decrease in HVA level was more pronounced in patients with severe mental deterioration and therefore appeared to be disease related.

Age Factors↗
PubMed1982

Excessive daytime sleepiness: a 1-year study in an unselected inpatient population.

A prospective epidemiological investigation of excessive daytime sleepiness (EDS) was carried out in an unselected inpatient population admitted to a general hospital during a 1-year period. The study comprised 2518 patients, 1347 female and 1171 male, aged 6-92 years (mean, 55.2). On the basis of histories and clinical and polysomnographic data, EDS was found in 28 cases (1.11%). Of these, 25 (0.99%; 18 female and 7 male; mean age, 61.3) had sleep apnea syndromes (SAS) with predominantly obstructive apnea. Two patients (0.07%; one female and one male; mean age, 65.5) had idiopathic CNS hypersomnia, and one male patient (0.03%) aged 48 years had a combination of narcolepsy and SAS. Differences and agreements of our findings with previous literature data are discussed. The present study shows that in an unselected inpatient population, EDS is a relatively common sleep disorder, usually found in mild to moderate forms. Because it is not severe, it disturbs only relatively domestic activities of elderly retired patients or others who do not work outside the home, and is often masked by other troubles. For these reasons, EDS in the aging population may pass unnoticed in epidemiological studies based only on data from sleep disorder centers.

Adolescent↗
PubMed1977

Clonazepam in cranial neuralgias.

A study of 21 patients has shown that clonazepam is an effective drug in preventing attacks of pain in trigeminal neuralgia and Sluder's syndrome. It has also been shown that no side effects result from long-term prescription of this drug.

Adult↗
PubMed1975

The metabolism of cyclic-3'-5'-adenosine monophosphate (cAMP) in diseased muscle.

Adenyl cyclase (AC) and cyclic nucleotide phosphodiesterase (PDE) have been studied in muscle from patients affected with muscular and neuromuscular diseases as well as in muscle of rats after experimental denervation. A diminution of AC was observed in Duchenne's dystrophy, in neurogenic atrophies, in inflammatory forms, in myasthenia and myotonia. PDE was diminished in Duchenne's dystrophy and increased in all other diseases considered. Both enzymes were increased in rat muscle after nerve transection. The possible mechanism underlying the biochemical alterations observed are discussed including unmasking of extra-activity due to changed metabolic environment, tissue destruction and activation of lysosomal activity.

Adenylyl Cyclases↗